This invention relates generally to telephone interconnection devices and more particularly to modular interface devices for use in telephone interchange systems. Specifically, the present invention relates to an orange field interface device for selectively interconnecting network telephone trunk lines with various subscriber owned and operated telephone lines and equipment.
Telephone interconnection and interchange systems include a wide variety of interface devices and arrangements for connecting network telephone trunk lines originating from a telephone company central office to individual customer or subscriber telephone keysets. Within such telephone interconnection and distribution systems located at a subscriber site, such as an office building, devices and equipment utilized for performing cross connections from central office network lines to other subscriber interchange equipment have traditionally been designated as green field devices. In addition, red field equipment has traditionally been utilized for performing key equipment connections, while yellow field devices are generally utilized to add special equipment and line functions, such as bells, lights, and the like, to the subscriber telephone lines. Furthermore, blue field devices and equipment have traditionally been designated for receiving connections from the green, red and yellow field devices and performing cross connections to customer keyset installations.
In the past, cables carrying network trunk lines from a telephone company central office have generally been introduced into an individual office building and connected to green field equipment and devices. Such devices are usually located in the basement of a building and are traditionally owned and maintained by one of the various telephone companies. Prior to the availability of privately owned subscriber telephone equipment not affiliated with the various telephone companies, it was generally unnecessary to determine and define the responsibility for maintenance and repair of specific devices and equipment within a particular telephone interchange system. Now, of course, private ownership of the devices and equipment of an entire telephone interconnection system, or at least portions thereof, located at a subscriber site has become quite common. Therefore, a need has arisen for an interface device which serves as an initial junction terminal between telephone company operated network trunk lines and the privately owned subscriber telephone interchange system. Such an interface device should permit simple and rapid conductor connections and easy differentiation between telephone company and subscriber owned lines and equipment. The device should also provide the capability of simple re-arrangement of connections between various subscriber telephone lines and available network trunk lines, and an ability to test the telephone lines to quickly determine whether malfunctions occurring there are located in the telephone company owned and operated equipment and trunk lines or within the subscriber owned and operated telephone interchange system.
Heretofore, network trunk line conductors have generally been hard wired onto quick connect blocks incorporated within the green field equipment. Such arrangements do not permit rapid and easy changing of conductor connections nor function to establish a separate and easily distinguishable juncture point or demarcation between the maintenance and repair responsibilities of the network trunk line supplier and the in-house or subscriber telephone interface equipment supplier. Thus, rapid and simple detection and differentiation between network supplier equipment and in-house subscriber equipment for testing and repair purposes has not been previously available.